Joe Schmidt believes England set the RBS 6 Nations "benchmark" with victory over Wales, leaving Ireland already chasing to keep up and hold on to their title.

Ireland boss Schmidt believes his side must improve "between 30 and 40 per cent" from their 26-3 win over Italy to stand any chance of reaching England's early level.

Stuart Lancaster's side set the standard with a 21-16 victory in Cardiff, and head coach Schmidt conceded Ireland are already playing catch-up.

Former schoolteacher Schmidt offered up a must-do-better report after tries from Conor Murray and Tommy O'Donnell while Leonardo Ghiraldini was in the sin-bin sealed victory in Rome.

"The benchmark was set by England last night: England just kept the pressure right on Wales and the physical nature of that battle means we've got a bit of work to do without a doubt," said Schmidt.

"And we'll have to roll our sleeves up early on next week and hopefully put together a sufficiently-improved performance to be competitive against France.

"We were between 30 and 40 per cent off that against Italy: we wouldn't have lived with them last night. And I thought Wales were pretty good.

"For us we certainly need to up our game. I do think that part of it was the pressure Italy put on us but, at the same time, I know we can do better than that and we're going to have to.

"I think Italy will improve through the tournament as well, they showed glimpses of what they are capable of. But you pick up two months after November with a number of changes: we had six of the starting 15 that we had this time last year, so that in itself presents a challenge."

Luckless flanker Sean O'Brien suffered a hamstring injury in the warm-up and was forced out of his first Test action since November 2013.

Ireland boss Schmidt lamented O'Brien's loss, with the Leinster back-rower only just fit after 14 months of shoulder problems.

Schmidt remains hopeful that O'Brien will be fit to face France in Dublin next weekend however, with hooker Rory Best also expected to be available.

Best was withdrawn in the second half as a precaution after taking a knock to the head.

"It was the very last thing Sean did in the warm-up: he just put his foot down, it slid out from under him and he twinged his hamstring," said Schmidt of O'Brien.

"His power's really good, it was probably a marginal decision at the time, but we didn't want a repeat of what happened when we came here last time where we lost a few.

"It was great he was able to be replaced by Tommy O'Donnell and the manner Tommy played.

"I'd be hopeful, I'd be quietly confident, but we will scan him when we get back to Dublin, probably tomorrow evening.

"Rory's fine, he did get a knock and we decided to err on the side of caution with him as well. He'll follow the return to play protocols, just because we want to be fairly careful there."